You are missing the point.* This person neglected both the snake by leaving an unsupervised live feeder in the cage, and the rodent by leaving it in a cage with no food or water. All the "crying about the BP dyeing [sic]" is because an abusive owner allowed an animal to be tortured until it died, and then proudly posted pictures of it on the internet. I would be equally upset to see a rodent treated this way, it is unacceptable regardless of the species involved.
*And just wrong in a legal sense. However in a religious or spiritual context your argument about all lives being equal may have merit.